THE Z-BOSON RESONANCE AND RADIATIVE-CORRECTIONS

The Z line shape is measured at LEP with an accuracy at the per mill l evel. Usually it is described in the Standard Model of electroweak int eractions with account of quantum corrections. Alternatively, one may attempt different model-independent approaches in order to extract qua ntities like mass and width of the Z boson. If a fit deviates from tha t in the standard approach, this may give hints for New Physics contri butions. I describe two model-independent approaches and compare their applications to LEP data with the Standard Model approach.